Modeling Approach to Capture Hyperelasticity and Temporary Bonds in Soft Polymer Networks

Abstract

Hyperelastic models developed by Gent, Ogden, and Dobrynin are modified to include a strain rate-dependent element. This strain rate dependence accounts for the breaking of temporary bonds in materials as opposed to the stretching of polymer chains. Accounting for the strain rate dependence in a material's mechanical response gives the ability to extract the modulus due to temporary and permanent bonds, strain hardening, and the relaxation time of dynamic materials. These modified models were tested against a wide range of elastomeric materials. The models were applicable across many network polymers, showing clear effects of temporary bonds in the material. Template spreadsheets for the developed models will be publicly and freely available, facilitating the application of these models to a range of complex soft materials.

Chemically Fueled Reinforcement of Polymer Hydrogels

“…In network solids, the total crosslink density, from both permanent and transient crosslinks, is proportional to G′. 24,25 Therefore, the presence of transient anhydride crosslinkers in the polymer causes G′ to be higher than the initial G′ or that of the material treated only with water. The peak storage modulus (G′ max ) of a given system thus corresponds to the maximum crosslink density.…”

“…The previously established behavior of Am/AA copolymers and the timescales of the experiments are consistent with the formation of temporary anhydride crosslinks (Scheme b). , After consumption of EDC, the anhydride linkers eventually hydrolyze, returning the material to the original state. In network solids, the total crosslink density, from both permanent and transient crosslinks, is proportional to G ′. , Therefore, the presence of transient anhydride crosslinkers in the polymer causes G ′ to be higher than the initial G ′ or that of the material treated only with water. The peak storage modulus ( G ′ max ) of a given system thus corresponds to the maximum crosslink density.…”

Educational series: characterizing crosslinked polymer networks

“…In many cases the sol fraction can impart unique properties to the overall material, such as facilitating energy dissipation. [62][63][64] The presence of soluble polymer segments within the network allows for increased mobility and the…”

“…In many cases the sol fraction can impart unique properties to the overall material, such as facilitating energy dissipation. [62][63][64] The presence of soluble polymer segments within the network allows for increased mobility and the ability to absorb and dissipate mechanical energy. However, it is important to consider that the sol fraction can also migrate or leach into the surrounding regions under specific conditions or environment.…”

Constraining effects on polymer chain relaxation in crosslinked supramolecular dual networks

“…The relationship between the Thy-DAT bond lifetime, activation energy, and modulus in a quiescent state has been discussed at length in the previous sections. To discuss the characteristics of transient bonds in energy dissipation (Hu et al, 2017) and the relationship of bond lifetime in anisotropic stretching, the recent Dobrynin-Konkolewicz model (Carrillo et al, 2013;Bennett et al, 2022) is applied. The microscale bond lifetime and the macroscale rubber mechanical properties of the DN in the small deformation range of a stress-strain experiment with varying strain rates lead to…”